Refrigerating apparatus



July 16, 1940- H. R. HElNTZEN 2,208,272

REFRIGERATING APPARATUS Filed Feb. 17, 1959 WITNESSES: f INVENTOR l/ EPOHEIA/IZ a ATTORNZZW Patented July 16, 1940 REFRIGEBATING APPARATUS Harry R. Heintzen, Philadelphia, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.; a corporation of Pennsylvania n -Application was, 11, 1939, Serial No. 256,921

11 Claims.

My invention relates to refrigerating apparatus and has for an object to provide improved apparatus of this kind. 1

A further object of the invention is to maintain the mean temperature of the media in a refrigerated zone at asubstantially constant value irrespective of changes in the temperature of the ambient atmosphere and the different rates of heat leakage into the zone which accompany variations in the temperature of the ambient atmosphere.

A further object of the invention is to provide improved means for adjusting the control mechanism of a refrigerating machine in response to changes in temperature of the ambient atmosphere whereby the mean temperature of the cooling element is increased and decreased with respective decreases and increases in temperature of the ambient atmosphere.

. 0 V These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

25 Fig. 1 is a diagrammatic view of a refrigerator 35 wherein I have shown my. invention applied to a conventional refrigerator ofthe domestic" type and including a cabinet structure l0 having insulated walls II for defining a zone or cooling chamber l2. A suitable element such as, for ex- 0 ample, a refrigerant evaporator I3 is employed flgr abstracting heat from the air in the chamber Refrigerant vaporized in the evaporator I3 is withdrawn therefrom through a conduit It by 45 means of a refrigerant condensing'unit, generally indicated at l5, and including a compressor l6 driven by an electric motor L1. The withdrawn vapor is compressed to a relatively high pressure by the compressor l6 and is delivered to 50 a condenser I8 through a conduit l9. Cooling of the condenser may be effected in any well understood manner such as, for example, by means of a fan 2| driven by an electric motor 22. The motor I! may be energized from a suitable source 55 of electrical energy (not shown) through line conductors L1 and La. The high pressure vapor delivered to the condenser I8 is cooled and condensed and the liquefied refrigerant is conveyed to the evaporator l3 through a conduit 23 having a suitable expansion device such as, for

example, a capillary tube 24 connected therein.

Operation of the condensing unit I5 is controlled by a, thermostat, preferably of the fluid type, and generally shown at 25. The thermostat 25 responds to the temperature of the evaporator l3 and includes an expansible bellows 26 that is connected by a tube 21 to a bulb or reservoir 28, the latter being disposed in heat transfer relation with a suitable portion of the evaporator B. The bulb 28, bellows 26 and tube 21 preferably contain a volatile fluid, the pressure of which increases and decreases with respective increases and decreases in the temperature of the bulb 28. The thermostat 25 includes a switch 29 which is opened and closed, respectively, as the temperature of the bulb 28 attains predetermined low and high values. As shown, the bellows 26 operates a lever 3| that is connected to the switch 29 by an over-center spring 32 or other suitable quick-make, quick-break device. A spring 33 opposes expansion of the bellows 26 and may be adjusted by a suitable adjusting device shown at 34 whereby the mean temperature of the evaporator l3 may be varied.

The insulated walls II of the cabinet structure l0 may be of conventional construction and defined by spaced inner and outer shells Ila and Nb having suitable heat insulating material He therebetween. As the construction of cabinets of the type shown at H! is well understood in the art, no further description of the same is deemed necessary.

The refrigerating machine described in the foregoing is of the compressor-condenser-expander type, but it will be understood that other suitable forms of refrigerating machines may be controlled in accordance with my invention. As the operation of a refrigerating machine of this type is well known, no detailed description of its operation is deemed. necessary other than to say that, as the temperature of the bulb 28 increases to a predetermined value, the thermostat 25 closes the switch 29 for energizing the motor I! whereby operation of the condensing unit 15 is started. Opening of the thermostat switch 29 in response to a second predetermined value terminates operation of the condensing unit IS. The evaporator I3 is, therefore, maintained at a predetermined mean temperature determined by the adjustment of the thermostat spring 33.

- in the temperature of the ambient atmosphere exterior of the zone for a given setting or adjustment of the thermostat 25. This operation is effected by transmitting heat to the thermostat, at a rate which varies with the temperature of the ambient atmosphere. A refrigerating system controlled in this manner is shown and claimed in the copending application of Leslie B. M. Bu-' chanan, Serial No."122,505, filed January 27, 1937, now matured into Patent No. 2,192,846, dated March 5, 1940, and assigned to Westinghouse Electric 8: Manufacturing Company.

In accordance with the present invention, a heat conducting member or fin 35 is provided for conducting heat to the bulb 28 at rates varying with the temperature of the atmosphere exteriorly of the cabinet). As shown in Fig. 1, the fin 35 is suitably connected at one extremity to the inner shell II a and at its other extremity to a portion of the suction tube I4 adjacent the evaporator I3. The thermostat bulb 28 is Secured to the fin 35 near its connection to the tube I4. The fin 35 may also be connected to the main body of the evaporator I 3 but is preferably connected to a portion of the evaporator I3 of low mass and low heat storage capacity in order that compensation of the 'control may be effected with a relatively small amount of heat flow from the shell Ila.

The temperature of the inner shell IIa is a function of outside or ambient temperature as heat leaks through the insulation He at rates varying withvchanges in outside temperature. The temperature of the fin 35 progressively de-- creases along its length from a'value corresponding to the temperature of shell Ila to a value corresponding to the temperature of the portion of the suction conduit I4 to which it is connected. The bulb 28 is fixed to an intermediate portion of the fin 35 having a temperature that is determined by the terminal temperatures of the fin 35 Operation As shown in the drawing, the thermostatic switch 29 is closed and; the condensing unit. therefore, operates to circulate refrigerant through the evaporator I3. The temperature of the evaporator I3 and, therefore, the temperature of the air in the chamber I'2is progressively decreased. Heat is abstracted from the fin 35 at this tim and, when the temperature of the bulb 28 is reduced to a predetermined value, the thermostatic switch 29 is opened for terminating circulation of refrigerant.

During inactive periods of the condensing unit I5, the temperatures of the air in the chamber I2 and of the evaporator l3 increase due, primarily, to heat leakage into the chamber I2 through the insulated walls II. The temperature of a the thermostatic bulb 28 increases because of the increase in evaporator temperature and the heat conducted thereto through the fin 35 from the the rate of heat flow through the insulated walls II and the fin 35 to the bulb 28 is substantially constant. Assuming an increase in ambient or' outside temperature, the amount of heat leakage into the zone or chamber I2 is increased and the amount of heat imparted to the bulb,28 through the fin 35 is increased. Therefore, a greater temperature difierence prevails between the portion of the fin to which the bulb 28 is attached and the portion of the fin 35 which is attached to the suction conduit I4. Accordingly, operation of the compressor I6 is initiated when the temperature of the suction conduit i4 is at a lower value than in the cycle of operation described heretofore. During operation of the compressor I 6 the temperature of the terminal portion of the fin 35 adjacent the suction conduit I4 and the temperature of the evaporator I3- of the compressor I 6 is terminated. It will be apparent, therefore, that the mean temperature of the evaporator i3 is reduced when the temperaturepf the ambient atmosphere is increased so that the increase in heat leakage into the zone I 2 is compensated for by the reduced evaporator temperature.

A decrease in ambient temperature effects an operation which isthe reverse of that described in connection with an increase in ambient temperature in that the amoimt of heat leaking into the chamber I2 is reduced and the amount of heat conveyed to the thermostatic bulb 28 by the fin 35 is reduced. Accordingly, the temperature of the evaporator I3 and the suction conduit it? are at higher values when the temperatures of the thermostatic bulb 28 are at the values at which starting and stopping of the compressor I6 are effected. Therefore, the mean temperature of the evaporator I3 is relatively high when the temperature of the ambient atmosphere is relatively low and the rate of heat leakage into the zone is low.

It will be apparent from the foregoing description that the fin 35 defines a heat transmitting element, one terminal temperature of which is determined by the temperature of the ambient atmosphere and the other terminal temperature of which is responsive to the temperature of the evaporator or cooling element. The thermostat element is connected to 'an intermediate portion of the fin 35 having a temperature that is determined conjointly by the terminal temperatures of the fin 35. The temperature of the bulb 28 at which the compressor is started and stopped are fixed. An increase in ambient temperature tends to increase one terminal portion of the fin and the intermediate portion thereof so that it will be apparent that the other terminal portion of the fin must be depressed to a lower temperature in order to compensate for the increased temperature at the other terminal portion of the fin.

Conversely a reduction in temperature of the embodiments. In the embodiment shown in Fig.

4, a fin 31 is employed for supporting the thermostatic bulb 28 and which has one terminal portion thereof secured to the outer shell Ill) and the inner terminal portion of the fin being disposed in heat transfer relation with the evaporator l3. The fin 31 extends through an opening 38 in the inner liner I la which opening 38 is preferably closed by a rigid sheet of heat insulating material 39. The fin 31 is not in contact with the inner liner Ila. The operation of the apparatus shown in Fig. 4 is similar to that described in connection with Fig. 1 and need not be repeated. In Fig. 4 the high terminal temperature of the fin 31 is responsive directly to the temperature of the ambient atmosphere as it is disposed in heat transfer relation with the outer shell llb, which, of course, operates at temperatures which are substantiallythe same as the temperatures of the ambient atmosphere. It will be apparent that the amount of heat conducted by the fin 31 in Fig. 4, from the ambient atmosphere to within the zone I2 is greater than the amount conducted by the fin 35 of Fig. 1. However, the advantage of the embodiment shown in Fig. 4 resides in the terminal portion of the fin 31 more closely following ambient temperature changes. In this connection, it will be understood that, in Fig. 1, a certain lag or interval may prevail between ambient temperature change and the change in temperature of the fin 35. In the embodiment shown in Fig. 4 the control would function in an anticipatory manner as the fin 31 would be subjected to the temperature change before the temperature of the air in the compartment I2 is affected.

As the operation of the control systems described heretofore is dependent upon the relative rate of heat transfer from the cabinet structure to the temperature responsive element 28 and from the element 28 to the evaporator l3, any desired relation between the temperature of the refrigerated zone and the ambient atmosphere may be obtained by varying the amount of thermal contact between these elements or by adjusting the position of the temperature responsive element relative the cabinet and theevaporator. Accordingly, the heat transferred between said elements may be such that the temperature of the air in the zone 12 is reduced as the temperature of the ambient atmosphere increases and vice versa. This method of control may be desirable in order to compensate for different service loads caused by opening the cabinet door and by cooling food products from different initial temperatures.

While I have shown my invention applied to a refrigerating system employing a condensing unit for circulating a volatile refrigerant through the cooling element, it will be understood that my invention may be applied to other forms of refrigerating systems. Furthermore, I have shown the heat conducting elements 35 and 31 disposed in heat transfer relation with the inner and outer shells of the cabinet structure and to the suction conduit and main evaporator body, respectively, but it will be understood that the terminal portions of the fin may be connected otherwise in any manner wherein they are affected by the temperature of the ambient atmosphere and of the cooling element. My invention broadly contemplates the employment of a. heat conducting member having a portion disposed in heat transfer relation with the thermostatic element of a control apparatus and other portions disposed, respectively, in heat transfer relation with the cooling element and the ambient atmosphere.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of a cabinet structure defining a zone to be cooled, cooling means for abstracting heat from the media in said zone, means for circulating refrigerant'through said'cooling means, thermostatic means for controlling the operation of the circulating means and including a temperature responsive element, and a heat conducting member having one portion thereof disposed-in heat transfer relation with the ambient atmosphere exteriorly of the zone and responsive to changes in temperature of the ambient atmosphere and a second portion thereof disposed in heat transfer relation with said cooling means, said temprature responsive element being connected to said member intermediate said first and second portions thereof.

2. In refrigerating apparatus, the combination of a cabinet structure defining a zone to be cooled, cooling means for abstracting heat from the media in said zone, means for circulating refrigerant through said cooling means, thermostatic means for controlling the operation of the circulating means and including a temperature responsive element, and a heat conducting member extending between a portion of the cabinet structureand said cooling means, said temperature responsive element being disposed in heat transfer relation with an intermediate portion of the heat conducting member.

3. In refrigerating apparatus, the combination of a cabinet structure having insulated walls defining a zone to be cooled, cooling means for abstracting heat from the media in said zone, means for circulating refrigerant through said cooling means, thermostatic means for controlling the operation of the circulating means and including a temperature responsive element, and a heat conducting member having a first portion thereof connected to the inner surface of the cabinet walls and a second portion thereof disposed in heat transfer relation with said cooling means,.said temperature responsive element being connected to the heat conducting member intermediate said first'and second portions thereof.

4. In refrigerating apparatus, the combination of a cabinet structure having spaced inner and outershells, said inner shell defining a chamber to be refrigerated, cooling means for abstracting heat from the media in said chamber, means for circulating refrigerant through said cooling means, a thermostat for controlling operation of the circulating means and including a tempera- D ture responsive element, and a member disposed for conducting heat from said inner shell to the cooling means; said temperature responsive element being connected to a portion of said member intermediate the inner shell and the cooling means whereby it responds to a temperature that is a function of the temperatures of the inner shell and of the cooling means.

5. In refrigerating apparatus, the combination the cooling means.

6. In refrigerating apparatus, the combination of a cabinet structure having spaced inner and outer shells, said inner shell defining a chamber to be refrigerated, cooling means for abstracting heatfrom the media in said chamber, means for circulating refrigerant through said cooling means, a thermostat for controlling operation of the circulating means and including a temperature responsive element and a member con necting said inner shell and the cooling means and providing for the conduction of heat from the former to the latter, said temperature responsive element being connected to a portion of the member intermediate the shell and the cooling means whereby it is affected by a temperature that is a function of both the temperature exteriorly of the chamber and the temperature of of a cabinet structure having spaced inner and outer shells, said inner shell defining a chamber to be refrigerated, cooling means for abstracting heat from the media in said chamber, means for circulating refrigerant through said cooling means, a thermostat for controlling operation of the circulating means and including a temperature responsive element disposed in heat transfer relation with said cooling means and means for conducting heat from said inner shell to the temperature responsive element at rates varying with changes in temperature of the atmosphere exteriorly of the cabinet structure.

7. In refrigerating apparatus, the combination of a cabinet structure, having spaced inner and outer shells, said inner shell enclosing a chamber to be refrigerated, an evaporator for abstracting heat from the media in said chamber, means for circulating refrigerant through said evaporator including a suction conduit, a thermostat for controlling operation of the circulating means and including a temperature responsive element disposed in heat transfer relation with a portion of said suction conduit adjacent the evaporator and a heat conducting fin connecting said inner shell and the temperature responsive element and pro viding for the conduction of heat therebetween,

8. In refrigerating apparatus, the combination of a cabinet structure having spaced inner and outer shells, said inner shell defining a chamber to be refrigerated, cooling means for abstracting heat from the media in said chamber, means for circulating refrigerant through said cooling means, a thermostat for controlling operation of the circulating means and including a temperature responsive element, and a member disposed in heat transfer relation with the outer shell and said cooling means and prfiidingfor the flow of both the temperature of the outer shell and v the temperature of the cooling means.

9. In refrigerating apparatus, the combination of a cabinet structure defining a zone to be cooled, cooling means for abstracting heat' from the media in said zone, means for circulating refrigerant through said cooling means, thermostatic means for controlling the operation of the circulating means and including a temperature responsive element, and a heat conducting member having one portion thereof disposed in the ambient atmosphere exteriorly of the zone and directly responsive to changes in temperature of the ambient atmosphere and a second portion thereof disclosed in heat transfer relation with the cooling means, said temperature responsive element being connected to said member intermediate the first and second portions thereof.

10. In refrigerating apparatus, the combination of a cabinet defining a chamber to be refrigerated, a cooling unit for abstracting heat from said chamber, a regulating device for controlling the temperature of said cooling unit, said regulating device including a thermostat, and two Dathsof non-gaseous material and of restricted heat-carrying capacity, one of said paths connecting said thermostat with the temperature prevailing exterior of said cabinet and the other of said paths connecting said thermostat with the cooling unit, said two paths tending to maintain said thermostat at a temperature intermediate of and bearing a substantially fixed ratio to the temperature of the cooling unit and the temperature prevailing exterior of said cabinet.

11. In refrigerating apparatus, the combination of a cabinet having aninterior shell defining a chamber to be refrigerated, a cooling unit for abstracting heat from said chamber, a regulating device for controlling the temperature of said cooling unit, said device including a thermostat, and two paths of non-gaseous material and of restricted heat-carrying capacity, one of said paths connecting said thermostat with the interior shell of said cabinet and the other of said paths connecting said thermostat with said cooling unit, said two paths tending to maintain said thermostat at a temperature intermediate of and bearing a substantially fixed ratio to the temperature of the cooling unit and the temperature of the interior shell of the cabinet.

HARRY R. rmm'rznu.

CERTIFICATE OF CORRECTION. Patent No. 2,208,272. July 16, 191m HARRY R. HEINTZEN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page l|., sec- 0nd co1umn,-line 19, claim 9, for the word "disclosed" read "disposed";

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of August, A-. D, 191w,

, Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

